<div dir="ltr"><div>Hi</div><div><br></div><div>I think running a TRANSITION STATE calculation would be a good idea, but you may need to use tighter convergence criteria for energies (EPS_SCF) and forces (MAX_FORCE). And also, you may specify a vector (see &DIMER_VECTOR subsection) for the dimer method, and a good initial guess could be the eigenvectors corresponding to your first imaginary vibrational mode (with the most negative frequency).</div><div><br></div><div>SL</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 24 January 2016 at 01:45, Natalie Austin <span dir="ltr"><<a href="mailto:natalie...@gmail.com" target="_blank">natalie...@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hello, <br><br>I ran a CI-NEB calculation on co2 adsorption on a metal from the physisorbed to chemisorbed state. After the NEB calculation completed I ran a VIBRATIONAL ANALYSIS on the structure from the NEB which would represent the transition state (I took the structure with the highest energy). I found 3 imaginary frequencies after the VIBRATIONAL ANALYSIS completed:<br><br> VIB| NORMAL MODES - CARTESIAN DISPLACEMENTS<br> VIB|<br> VIB| 1 2 3<br> VIB|Frequency (cm^-1) -373.959745 -155.894278 -82.219450<br> VIB|Intensities 0.000000 0.000000 0.000000<br> VIB|Red.Masses (a.u.) 15.645084 12.197575 14.794711<br> VIB|Frc consts (a.u.) -0.000783 -0.000018 -0.000002<br> ATOM EL X Y Z X Y Z X Y Z<br> 56 O 0.04 0.11 -0.92 -0.02 -0.02 0.19 0.51 0.21 0.24<br> 57 C 0.08 0.06 -0.28 -0.25 0.09 -0.94 0.50 0.20 -0.10<br> 58 O 0.20 0.04 0.04 -0.04 0.02 -0.09 0.57 0.12 -0.01<br><br><br> VIB| 4 5 6<br> VIB|Frequency (cm^-1) 233.171137 297.756764 384.024573<br> VIB|Intensities 0.000000 0.000000 0.000000<br> VIB|Red.Masses (a.u.) 14.149167 15.693032 15.822496<br> VIB|Frc consts (a.u.) 0.000107 0.000316 0.000881<br> ATOM EL X Y Z X Y Z X Y Z<br> 56 O -0.07 0.27 -0.00 -0.30 0.74 0.08 -0.01 -0.19 0.06<br> 57 C -0.17 0.65 0.13 -0.16 0.23 0.04 -0.17 0.11 -0.05<br> 58 O -0.22 0.64 -0.05 0.13 -0.50 0.13 0.14 0.09 0.94<br><br><br>I wanted to know the best way to get rid all but one of these imaginary frequencies? The first thing I'm attempting to do is run a TRANSITION STATE calculation on the structure. <br>From what I read on this board another option would be to change some of the XYZ coordinates by using adding a fraction of the atomic displacements to the coordinates from one of the imaginary modes and then run TRANSITION STATE calculation on the new structure.<br><br>Or should I change the coordinates (using the atomic displacements) and then use the new structure to rerun the NEB and then perform the vibrational analysis again?<br>I've included my CI-NEB, TRANSITION STATE, and VIBRATIONAL ANALYSIS inputs.<br> <br>Any advice on what else I could do to get rid of all but one of the imaginary frequencies (or if I'm taking the right steps already) would be appreciated.<br><br>Thanks,<br><br>Natalie<span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888">
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